DESCRIPTION (provided by investigator): Although research has demonstrated that close, supportive relationships foster psychological well-being, the mechanisms and boundary conditions for such effects are not well understood. The proposed research investigates this issue by determining how physical separations from spouses or cohabiting partners affect day-to-day emotion regulation and overall psychological well being. This research will answer the following questions: (1) What are the day-to-day emotional, behavioral, and physiological effects of physical separations from spouses or cohabiting partners? (2) What aspects of partners' interactions during the separation mediate these effects? (3) What are the long-term psychological consequences of repeated or extended physical separations? (4) Are separation effects moderated by individual differences in physiological capacities and interpersonal strategies for emotion regulation? Study 1 will assess married and cohabitating couples' day-to-day positive and negative emotions, social interactions, and stress-related neuroendocrine activity (i.e., cortisol levels) before, during, and after a naturally occurring 4-6 day separation (for example, one partner's business trip). It will establish the basic emotional and physiological effects of short-term separations, determine whether these effects are mediated by separation-related changes in partners' interactions, and determine whether separation effects are moderated by individual differences in physiological capacities and interpersonal strategies for emotion regulation (vagal tone and attachment style, respectively). Study 2 will determine whether the same effects, mediators, and moderators explain couples' responses to repeated or extended physical separations. It will also examine the potential consequences of repeated and extended separations for partners' mutual attachment and overall psychological well-being. In summary, the proposed research will produce a detailed roadmap of the specific emotional, behavioral, and physiological effects of physical separations from spouses or cohabiting partners, and the potential mediators and moderators of these effects. This information will make a significant contribution to research on the multiple biobehavioral processes through which close relationships influence day-to-day emotion regulation and long-term psychological well-being.